package com.cws4cloud.cws.mall.xsm.util;

import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;


/**
* Encodes and decodes to and from Base64 notation.
*
* <p>
* Change Log:
* </p>
* <ul>
*  <li>v2.1 - Cleaned up javadoc comments and unused variables and methods. Added
*   some convenience methods for reading and writing to and from files.</li>
*  <li>v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on systems
*   with other encodings (like EBCDIC).</li>
*  <li>v2.0.1 - Fixed an error when decoding a single byte, that is, when the
*   encoded data was a single byte.</li>
*  <li>v2.0 - I got rid of methods that used booleans to set options.
*   Now everything is more consolidated and cleaner. The code now detects
*   when data that's being decoded is gzip-compressed and will decompress it
*   automatically. Generally things are cleaner. You'll probably have to
*   change some method calls that you were making to support the new
*   options format (<tt>int</tt>s that you "OR" together).</li>
*  <li>v1.5.1 - Fixed bug when decompressing and decoding to a
*   byte[] using <tt>decode( String s, boolean gzipCompressed )</tt>.
*   Added the ability to "suspend" encoding in the Output Stream so
*   you can turn on and off the encoding if you need to embed base64
*   data in an otherwise "normal" stream (like an XML file).</li>
*  <li>v1.5 - Output stream pases on flush() command but doesn't do anything itself.
*      This helps when using GZIP streams.
*      Added the ability to GZip-compress objects before encoding them.</li>
*  <li>v1.4 - Added helper methods to read/write files.</li>
*  <li>v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.</li>
*  <li>v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input stream
*      where last buffer being read, if not completely full, was not returned.</li>
*  <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.</li>
*  <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li>
* </ul>
*
* <p>
* I am placing this code in the Public Domain. Do with it as you will.
* This software comes with no guarantees or warranties but with
* plenty of well-wishing instead!
* Please visit <a href="http://iharder.net/base64">http://iharder.net/base64</a>
* periodically to check for updates or to contribute improvements.
* </p>
*
* @author Robert Harder
* @author rob@iharder.net
* @version 2.1
*/
public class Base64
{
  private static Logger logger = Logger.getLogger(Base64.class.getCanonicalName());

  /* ********  P U B L I C   F I E L D S  ******** */

  /** No options specified. Value is zero. */
  public final static int NO_OPTIONS = 0;

  /** Specify encoding. */
  public final static int ENCODE = 1;

  /** Specify decoding. */
  public final static int DECODE = 0;

  /** Specify that data should be gzip-compressed. */
  public final static int GZIP = 2;

  /** Don't break lines when encoding (violates strict Base64 specification) */
  public final static int DONT_BREAK_LINES = 8;

  /* ********  P R I V A T E   F I E L D S  ******** */

  /** Maximum line length (76) of Base64 output. */
  private final static int MAX_LINE_LENGTH = 76;

  /** The equals sign (=) as a byte. */
  private final static byte EQUALS_SIGN = (byte)'=';

  /** The new line character (\n) as a byte. */
  private final static byte NEW_LINE = (byte)'\n';

  /** Preferred encoding. */
  private final static String PREFERRED_ENCODING = "UTF-8";

  /** The 64 valid Base64 values. */
  private final static byte[] ALPHABET;
  private final static byte[] _NATIVE_ALPHABET = /* May be something funny like EBCDIC */
  { (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G', (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
        (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z', (byte)'a', (byte)'b',
        (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g', (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n', (byte)'o', (byte)'p',
        (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z', (byte)'0', (byte)'1', (byte)'2', (byte)'3',
        (byte)'4', (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/' };

  /** Determine which ALPHABET to use. */
  static
  {
     byte[] __bytes;
     try
     {
        __bytes = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".getBytes(PREFERRED_ENCODING);
     } // end try
     catch (java.io.UnsupportedEncodingException use)
     {
        __bytes = _NATIVE_ALPHABET; // Fall back to native encoding
     } // end catch
     ALPHABET = __bytes;
  } // end static

  /**
   * Translates a Base64 value to either its 6-bit reconstruction value
   * or a negative number indicating some other meaning.
   **/
  private final static byte[] DECODABET = { -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal  0 -  8
        -5, -5, // Whitespace: Tab and Linefeed
        -9, -9, // Decimal 11 - 12
        -5, // Whitespace: Carriage Return
        -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 - 26
        -9, -9, -9, -9, -9, // Decimal 27 - 31
        -5, // Whitespace: Space
        -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
        62, // Plus sign at decimal 43
        -9, -9, -9, // Decimal 44 - 46
        63, // Slash at decimal 47
        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
        -9, -9, -9, // Decimal 58 - 60
        -1, // Equals sign at decimal 61
        -9, -9, -9, // Decimal 62 - 64
        0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through 'N'
        14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O' through 'Z'
        -9, -9, -9, -9, -9, -9, // Decimal 91 - 96
        26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a' through 'm'
        39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n' through 'z'
        -9, -9, -9, -9 // Decimal 123 - 126
  /*,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 127 - 139
   -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
   -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
   -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
   -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
   -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
   -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
   -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
   -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
   -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 */
  };

  // I think I end up not using the BAD_ENCODING indicator.
  //private final static byte BAD_ENCODING    = -9; // Indicates error in encoding
  private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding
  private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding

  /** Defeats instantiation. */
  private Base64()
  {
  }

  /* ********  E N C O D I N G   M E T H O D S  ******** */

  /**
   * Encodes up to the first three bytes of array <var>threeBytes</var>
   * and returns a four-byte array in Base64 notation.
   * The actual number of significant bytes in your array is
   * given by <var>numSigBytes</var>.
   * The array <var>threeBytes</var> needs only be as big as
   * <var>numSigBytes</var>.
   * Code can reuse a byte array by passing a four-byte array as <var>b4</var>.
   *
   * @param b4 A reusable byte array to reduce array instantiation
   * @param threeBytes the array to convert
   * @param numSigBytes the number of significant bytes in your array
   * @return four byte array in Base64 notation.
   * @since 1.5.1
   */
  private static byte[] encode3to4(byte[] b4, byte[] threeBytes, int numSigBytes)
  {
     encode3to4(threeBytes, 0, numSigBytes, b4, 0);
     return b4;
  } // end encode3to4

  /**
   * Encodes up to three bytes of the array <var>source</var>
   * and writes the resulting four Base64 bytes to <var>destination</var>.
   * The source and destination arrays can be manipulated
   * anywhere along their length by specifying
   * <var>srcOffset</var> and <var>destOffset</var>.
   * This method does not check to make sure your arrays
   * are large enough to accomodate <var>srcOffset</var> + 3 for
   * the <var>source</var> array or <var>destOffset</var> + 4 for
   * the <var>destination</var> array.
   * The actual number of significant bytes in your array is
   * given by <var>numSigBytes</var>.
   *
   * @param source the array to convert
   * @param srcOffset the index where conversion begins
   * @param numSigBytes the number of significant bytes in your array
   * @param destination the array to hold the conversion
   * @param destOffset the index where output will be put
   * @return the <var>destination</var> array
   * @since 1.3
   */
  private static byte[] encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset)
  {
     //           1         2         3
     // 01234567890123456789012345678901 Bit position
     // --------000000001111111122222222 Array position from threeBytes
     // --------|    ||    ||    ||    | Six bit groups to index ALPHABET
     //          >>18  >>12  >> 6  >> 0  Right shift necessary
     //                0x3f  0x3f  0x3f  Additional AND

     // Create buffer with zero-padding if there are only one or two
     // significant bytes passed in the array.
     // We have to shift left 24 in order to flush out the 1's that appear
     // when Java treats a value as negative that is cast from a byte to an int.
     int inBuff = (numSigBytes > 0 ? ((source[srcOffset] << 24) >>> 8) : 0) | (numSigBytes > 1 ? ((source[srcOffset + 1] << 24) >>> 16) : 0)
           | (numSigBytes > 2 ? ((source[srcOffset + 2] << 24) >>> 24) : 0);

     switch (numSigBytes)
     {
        case 3:
           destination[destOffset] = ALPHABET[(inBuff >>> 18)];
           destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
           destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
           destination[destOffset + 3] = ALPHABET[(inBuff) & 0x3f];
           return destination;

        case 2:
           destination[destOffset] = ALPHABET[(inBuff >>> 18)];
           destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
           destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
           destination[destOffset + 3] = EQUALS_SIGN;
           return destination;

        case 1:
           destination[destOffset] = ALPHABET[(inBuff >>> 18)];
           destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
           destination[destOffset + 2] = EQUALS_SIGN;
           destination[destOffset + 3] = EQUALS_SIGN;
           return destination;

        default:
           return destination;
     } // end switch
  } // end encode3to4

  /**
   * Serializes an object and returns the Base64-encoded
   * version of that serialized object. If the object
   * cannot be serialized or there is another error,
   * the method will return <tt>null</tt>.
   * The object is not GZip-compressed before being encoded.
   *
   * @param serializableObject The object to encode
   * @return The Base64-encoded object
   * @since 1.4
   */
  public static String encodeObject(java.io.Serializable serializableObject)
  {
     return encodeObject(serializableObject, NO_OPTIONS);
  } // end encodeObject

  /**
   * Serializes an object and returns the Base64-encoded
   * version of that serialized object. If the object
   * cannot be serialized or there is another error,
   * the method will return <tt>null</tt>.
   * <p>
   * Valid options:<pre>
   *   GZIP: gzip-compresses object before encoding it.
   *   DONT_BREAK_LINES: don't break lines at 76 characters
   *     <i>Note: Technically, this makes your encoding non-compliant.</i>
   * </pre>
   * <p>
   * Example: <code>encodeObject( myObj, Base64.GZIP )</code> or
   * <p>
   * Example: <code>encodeObject( myObj, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
   *
   * @param serializableObject The object to encode
   * @param options Specified options
   * @return The Base64-encoded object
   * @see Base64#GZIP
   * @see Base64#DONT_BREAK_LINES
   * @since 2.0
   */
  public static String encodeObject(java.io.Serializable serializableObject, int options)
  {
     // Streams
     java.io.ByteArrayOutputStream baos = null;
     java.io.OutputStream b64os = null;
     java.io.ObjectOutputStream oos = null;
     java.util.zip.GZIPOutputStream gzos = null;

     // Isolate options
     int gzip = (options & GZIP);
     int dontBreakLines = (options & DONT_BREAK_LINES);

     try
     {
        // ObjectOutputStream -> (GZIP) -> Base64 -> ByteArrayOutputStream
        baos = new java.io.ByteArrayOutputStream();
        b64os = new OutputStream(baos, ENCODE | dontBreakLines);

        // GZip?
        if (gzip == GZIP)
        {
           gzos = new java.util.zip.GZIPOutputStream(b64os);
           oos = new java.io.ObjectOutputStream(gzos);
        } // end if: gzip
        else oos = new java.io.ObjectOutputStream(b64os);

        oos.writeObject(serializableObject);
     } // end try
     catch (IOException e)
     {
        e.printStackTrace();
        return null;
     } // end catch
     finally
     {
        try
        {
           oos.close();
        }
        catch (Exception e)
        {
        }
        try
        {
           gzos.close();
        }
        catch (Exception e)
        {
        }
        try
        {
           b64os.close();
        }
        catch (Exception e)
        {
        }
        try
        {
           baos.close();
        }
        catch (Exception e)
        {
        }
     } // end finally

     // Return value according to relevant encoding.
     try
     {
        return new String(baos.toByteArray(), PREFERRED_ENCODING);
     } // end try
     catch (java.io.UnsupportedEncodingException uue)
     {
        return new String(baos.toByteArray());
     } // end catch

  } // end encode

  /**
   * Encodes a byte array into Base64 notation.
   * Does not GZip-compress data.
   *
   * @param source The data to convert
   * @return the encode bytes
   * @since 1.4
   */
  public static String encodeBytes(byte[] source)
  {
     return encodeBytes(source, 0, source.length, NO_OPTIONS);
  } // end encodeBytes

  /**
   * Encodes a byte array into Base64 notation.
   * <p>
   * Valid options:<pre>
   *   GZIP: gzip-compresses object before encoding it.
   *   DONT_BREAK_LINES: don't break lines at 76 characters
   *     <i>Note: Technically, this makes your encoding non-compliant.</i>
   * </pre>
   * <p>
   * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
   * <p>
   * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
   *
   *
   * @param source The data to convert
   * @param options Specified options
   * @return the encoded bytes
   * @see Base64#GZIP
   * @see Base64#DONT_BREAK_LINES
   * @since 2.0
   */
  public static String encodeBytes(byte[] source, int options)
  {
     return encodeBytes(source, 0, source.length, options);
  } // end encodeBytes

  /**
   * Encodes a byte array into Base64 notation.
   * Does not GZip-compress data.
   *
   * @param source The data to convert
   * @param off Offset in array where conversion should begin
   * @param len Length of data to convert
   * @return the text node
   * @since 1.4
   */
  public static String encodeBytes(byte[] source, int off, int len)
  {
     return encodeBytes(source, off, len, NO_OPTIONS);
  } // end encodeBytes

  /**
   * Encodes a byte array into Base64 notation.
   * <p>
   * Valid options:<pre>
   *   GZIP: gzip-compresses object before encoding it.
   *   DONT_BREAK_LINES: don't break lines at 76 characters
   *     <i>Note: Technically, this makes your encoding non-compliant.</i>
   * </pre>
   * <p>
   * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
   * <p>
   * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
   *
   *
   * @param source The data to convert
   * @param off Offset in array where conversion should begin
   * @param len Length of data to convert
   * @param options Specified options
   * @see Base64#GZIP
   * @see Base64#DONT_BREAK_LINES
   * @return the text node
   * @since 2.0
   */
  public static String encodeBytes(byte[] source, int off, int len, int options)
  {
     // Isolate options
     int dontBreakLines = (options & DONT_BREAK_LINES);
     int gzip = (options & GZIP);

     // Compress?
     if (gzip == GZIP)
     {
        java.io.ByteArrayOutputStream baos = null;
        java.util.zip.GZIPOutputStream gzos = null;
        OutputStream b64os = null;

        try
        {
           // GZip -> Base64 -> ByteArray
           baos = new java.io.ByteArrayOutputStream();
           b64os = new OutputStream(baos, ENCODE | dontBreakLines);
           gzos = new java.util.zip.GZIPOutputStream(b64os);

           gzos.write(source, off, len);
           gzos.close();
        } // end try
        catch (IOException e)
        {
           e.printStackTrace();
           return null;
        } // end catch
        finally
        {
           try
           {
              gzos.close();
           }
           catch (Exception e)
           {
           }
           try
           {
              b64os.close();
           }
           catch (Exception e)
           {
           }
           try
           {
              baos.close();
           }
           catch (Exception e)
           {
           }
        } // end finally

        // Return value according to relevant encoding.
        try
        {
           return new String(baos.toByteArray(), PREFERRED_ENCODING);
        } // end try
        catch (java.io.UnsupportedEncodingException uue)
        {
           return new String(baos.toByteArray());
        } // end catch
     } // end if: compress

     // Else, don't compress. Better not to use streams at all then.
     else
     {
        // Convert option to boolean in way that code likes it.
        boolean breakLines = dontBreakLines == 0;

        int len43 = len * 4 / 3;
        byte[] outBuff = new byte[(len43) // Main 4:3
              + ((len % 3) > 0 ? 4 : 0) // Account for padding
              + (breakLines ? (len43 / MAX_LINE_LENGTH) : 0)]; // New lines
        int d = 0;
        int e = 0;
        int len2 = len - 2;
        int lineLength = 0;
        for (; d < len2; d += 3, e += 4)
        {
           encode3to4(source, d + off, 3, outBuff, e);

           lineLength += 4;
           if (breakLines && lineLength == MAX_LINE_LENGTH)
           {
              outBuff[e + 4] = NEW_LINE;
              e++;
              lineLength = 0;
           } // end if: end of line
        } // en dfor: each piece of array

        if (d < len)
        {
           encode3to4(source, d + off, len - d, outBuff, e);
           e += 4;
        } // end if: some padding needed

        // Return value according to relevant encoding.
        try
        {
           return new String(outBuff, 0, e, PREFERRED_ENCODING);
        } // end try
        catch (java.io.UnsupportedEncodingException uue)
        {
           return new String(outBuff, 0, e);
        } // end catch

     } // end else: don't compress

  } // end encodeBytes

  /* ********  D E C O D I N G   M E T H O D S  ******** */

  /**
   * Decodes four bytes from array <var>source</var>
   * and writes the resulting bytes (up to three of them)
   * to <var>destination</var>.
   * The source and destination arrays can be manipulated
   * anywhere along their length by specifying
   * <var>srcOffset</var> and <var>destOffset</var>.
   * This method does not check to make sure your arrays
   * are large enough to accomodate <var>srcOffset</var> + 4 for
   * the <var>source</var> array or <var>destOffset</var> + 3 for
   * the <var>destination</var> array.
   * This method returns the actual number of bytes that
   * were converted from the Base64 encoding.
   *
   *
   * @param source the array to convert
   * @param srcOffset the index where conversion begins
   * @param destination the array to hold the conversion
   * @param destOffset the index where output will be put
   * @return the number of decoded bytes converted
   * @since 1.3
   */
  private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset)
  {
     // Example: Dk==
     if (source[srcOffset + 2] == EQUALS_SIGN)
     {
        // Two ways to do the same thing. Don't know which way I like best.
        //int outBuff =   ( ( DECODABET[ source[ srcOffset    ] ] << 24 ) >>>  6 )
        //              | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 );
        int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18) | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12);

        destination[destOffset] = (byte)(outBuff >>> 16);
        return 1;
     }

     // Example: DkL=
     else if (source[srcOffset + 3] == EQUALS_SIGN)
     {
        // Two ways to do the same thing. Don't know which way I like best.
        //int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] << 24 ) >>>  6 )
        //              | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
        //              | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 );
        int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18) | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
              | ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6);

        destination[destOffset] = (byte)(outBuff >>> 16);
        destination[destOffset + 1] = (byte)(outBuff >>> 8);
        return 2;
     }

     // Example: DkLE
     else
     {
        try
        {
           // Two ways to do the same thing. Don't know which way I like best.
           //int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] << 24 ) >>>  6 )
           //              | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
           //              | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 )
           //              | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 );
           int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18) | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
                 | ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6) | ((DECODABET[source[srcOffset + 3]] & 0xFF));

           destination[destOffset] = (byte)(outBuff >> 16);
           destination[destOffset + 1] = (byte)(outBuff >> 8);
           destination[destOffset + 2] = (byte)(outBuff);

           return 3;
        }
        catch (Exception e)
        {
           logger.log(Level.FINE,"" + source[srcOffset] + ": " + (DECODABET[source[srcOffset]]));
           logger.log(Level.FINE,"" + source[srcOffset + 1] + ": " + (DECODABET[source[srcOffset + 1]]));
           logger.log(Level.FINE,"" + source[srcOffset + 2] + ": " + (DECODABET[source[srcOffset + 2]]));
           logger.log(Level.FINE,"" + source[srcOffset + 3] + ": " + (DECODABET[source[srcOffset + 3]]));
           return -1;
        } //end catch
     }
  } // end decodeToBytes

  /**
   * Very low-level access to decoding ASCII characters in
   * the form of a byte array. Does not support automatically
   * gunzipping or any other "fancy" features.
   *
   * @param source The Base64 encoded data
   * @param off    The offset of where to begin decoding
   * @param len    The length of characters to decode
   * @return decoded data
   * @since 1.3
   */
  public static byte[] decode(byte[] source, int off, int len)
  {
     int len34 = len * 3 / 4;
     byte[] outBuff = new byte[len34]; // Upper limit on size of output
     int outBuffPosn = 0;

     byte[] b4 = new byte[4];
     int b4Posn = 0;
     int i = 0;
     byte sbiCrop = 0;
     byte sbiDecode = 0;
     for (i = off; i < off + len; i++)
     {
        sbiCrop = (byte)(source[i] & 0x7f); // Only the low seven bits
        sbiDecode = DECODABET[sbiCrop];

        if (sbiDecode >= WHITE_SPACE_ENC) // White space, Equals sign or better
        {
           if (sbiDecode >= EQUALS_SIGN_ENC)
           {
              b4[b4Posn++] = sbiCrop;
              if (b4Posn > 3)
              {
                 outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn);
                 b4Posn = 0;

                 // If that was the equals sign, break out of 'for' loop
                 if (sbiCrop == EQUALS_SIGN)
                    break;
              } // end if: quartet built

           } // end if: equals sign or better

        } // end if: white space, equals sign or better
        else
        {
           throw new IllegalStateException("Bad Base64 input character at " + i + ": " + source[i] + "(decimal)");
        } // end else:
     } // each input character

     byte[] out = new byte[outBuffPosn];
     System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
     return out;
  } // end decode

  /**
   * Decodes data from Base64 notation, automatically
   * detecting gzip-compressed data and decompressing it.
   *
   * @param s the string to decode
   * @return the decoded data
   * @since 1.4
   */
  public static byte[] decode(String s)
  {
     byte[] bytes;
     try
     {
        bytes = s.getBytes(PREFERRED_ENCODING);
     } // end try
     catch (java.io.UnsupportedEncodingException uee)
     {
        bytes = s.getBytes();
     } // end catch
     //</change>

     // Decode
     bytes = decode(bytes, 0, bytes.length);

     // Check to see if it's gzip-compressed
     // GZIP Magic Two-Byte Number: 0x8b1f (35615)
     if (bytes != null && bytes.length >= 4)
     {

        int head = (bytes[0] & 0xff) | ((bytes[1] << 8) & 0xff00);
        if (java.util.zip.GZIPInputStream.GZIP_MAGIC == head)
        {
           java.io.ByteArrayInputStream bais = null;
           java.util.zip.GZIPInputStream gzis = null;
           java.io.ByteArrayOutputStream baos = null;
           byte[] buffer = new byte[2048];
           int length = 0;

           try
           {
              baos = new java.io.ByteArrayOutputStream();
              bais = new java.io.ByteArrayInputStream(bytes);
              gzis = new java.util.zip.GZIPInputStream(bais);

              while ((length = gzis.read(buffer)) >= 0)
              {
                 baos.write(buffer, 0, length);
              } // end while: reading input

              // No error? Get new bytes.
              bytes = baos.toByteArray();

           } // end try
           catch (IOException e)
           {
              // Just return originally-decoded bytes
           } // end catch
           finally
           {
              try
              {
                 baos.close();
              }
              catch (Exception e)
              {
              }
              try
              {
                 gzis.close();
              }
              catch (Exception e)
              {
              }
              try
              {
                 bais.close();
              }
              catch (Exception e)
              {
              }
           } // end finally

        } // end if: gzipped
     } // end if: bytes.length >= 2

     return bytes;
  } // end decode

  /**
   * Attempts to decode Base64 data and deserialize a Java
   * Object within. Returns <tt>null</tt> if there was an error.
   *
   * @param encodedObject The Base64 data to decode
   * @return The decoded and deserialized object
   * @since 1.5
   */
  public static Object decodeToObject(String encodedObject)
  {
     // Decode and gunzip if necessary
     byte[] objBytes = decode(encodedObject);

     java.io.ByteArrayInputStream bais = null;
     java.io.ObjectInputStream ois = null;
     Object obj = null;

     try
     {
        bais = new java.io.ByteArrayInputStream(objBytes);
        ois = new java.io.ObjectInputStream(bais);

        obj = ois.readObject();
     } // end try
     catch (IOException e)
     {
        e.printStackTrace();
        obj = null;
     } // end catch
     catch (ClassNotFoundException e)
     {
        e.printStackTrace();
        obj = null;
     } // end catch
     finally
     {
        try
        {
           bais.close();
        }
        catch (Exception e)
        {
        }
        try
        {
           ois.close();
        }
        catch (Exception e)
        {
        }
     } // end finally

     return obj;
  } // end decodeObject

  /**
   * Convenience method for encoding data to a file.
   *
   * @param dataToEncode byte array of data to encode in base64 form
   * @param filename Filename for saving encoded data
   * @return <tt>true</tt> if successful, <tt>false</tt> otherwise
   *
   * @since 2.1
   */
  public static boolean encodeToFile(byte[] dataToEncode, String filename)
  {
     boolean success = false;
     OutputStream bos = null;
     try
     {
        bos = new OutputStream(new java.io.FileOutputStream(filename), Base64.ENCODE);
        bos.write(dataToEncode);
        success = true;
     } // end try
     catch (IOException e)
     {

        success = false;
     } // end catch: IOException
     finally
     {
        try
        {
           bos.close();
        }
        catch (Exception e)
        {
        }
     } // end finally

     return success;
  } // end encodeToFile

  /**
   * Convenience method for decoding data to a file.
   *
   * @param dataToDecode Base64-encoded data as a string
   * @param filename Filename for saving decoded data
   * @return <tt>true</tt> if successful, <tt>false</tt> otherwise
   *
   * @since 2.1
   */
  public static boolean decodeToFile(String dataToDecode, String filename)
  {
     boolean success = false;
     OutputStream bos = null;
     try
     {
        bos = new OutputStream(new java.io.FileOutputStream(filename), Base64.DECODE);
        bos.write(dataToDecode.getBytes(PREFERRED_ENCODING));
        success = true;
     } // end try
     catch (IOException e)
     {
        success = false;
     } // end catch: IOException
     finally
     {
        try
        {
           bos.close();
        }
        catch (Exception e)
        {
        }
     } // end finally

     return success;
  } // end decodeToFile

  /**
   * Convenience method for reading a base64-encoded
   * file and decoding it.
   *
   * @param filename Filename for reading encoded data
   * @return decoded byte array or null if unsuccessful
   *
   * @since 2.1
   */
  public static byte[] decodeFromFile(String filename)
  {
     byte[] decodedData = null;
     InputStream bis = null;
     try
     {
        // Set up some useful variables
        java.io.File file = new java.io.File(filename);
        byte[] buffer = null;
        int length = 0;
        int numBytes = 0;

        // Check for size of file
        if (file.length() > Integer.MAX_VALUE)
        {
           throw new IllegalStateException("File is too big for this convenience method (" + file.length() + " bytes).");
        } // end if: file too big for int index
        buffer = new byte[(int)file.length()];

        // Open a stream
        bis = new InputStream(new java.io.BufferedInputStream(new java.io.FileInputStream(file)), Base64.DECODE);

        // Read until done
        while ((numBytes = bis.read(buffer, length, 4096)) >= 0)
           length += numBytes;

        // Save in a variable to return
        decodedData = new byte[length];
        System.arraycopy(buffer, 0, decodedData, 0, length);

     } // end try
     catch (IOException e)
     {
        throw new IllegalStateException("Error decoding from file " + filename);
     } // end catch: IOException
     finally
     {
        try
        {
           bis.close();
        }
        catch (Exception e)
        {
        }
     } // end finally

     return decodedData;
  } // end decodeFromFile

  /**
   * Convenience method for reading a binary file
   * and base64-encoding it.
   *
   * @param filename Filename for reading binary data
   * @return base64-encoded string or null if unsuccessful
   *
   * @since 2.1
   */
  public static String encodeFromFile(String filename)
  {
     String encodedData = null;
     InputStream bis = null;
     try
     {
        // Set up some useful variables
        java.io.File file = new java.io.File(filename);
        byte[] buffer = new byte[(int)(file.length() * 1.4)];
        int length = 0;
        int numBytes = 0;

        // Open a stream
        bis = new InputStream(new java.io.BufferedInputStream(new java.io.FileInputStream(file)), Base64.ENCODE);

        // Read until done
        while ((numBytes = bis.read(buffer, length, 4096)) >= 0)
           length += numBytes;

        // Save in a variable to return
        encodedData = new String(buffer, 0, length, Base64.PREFERRED_ENCODING);

     } // end try
     catch (IOException e)
     {
        throw new IllegalStateException("Error encoding from file " + filename);
     } // end catch: IOException
     finally
     {
        try
        {
           bis.close();
        }
        catch (Exception e)
        {
        }
     } // end finally

     return encodedData;
  } // end encodeFromFile

  /* ********  I N N E R   C L A S S   I N P U T S T R E A M  ******** */

  /**
   * A {@link InputStream} will read data from another
   * <tt>java.io.InputStream</tt>, given in the constructor,
   * and encode/decode to/from Base64 notation on the fly.
   *
   * @see Base64
   * @since 1.3
   */
  public static class InputStream extends java.io.FilterInputStream
  {
     private boolean encode; // Encoding or decoding
     private int position; // Current position in the buffer
     private byte[] buffer; // Small buffer holding converted data
     private int bufferLength; // Length of buffer (3 or 4)
     private int numSigBytes; // Number of meaningful bytes in the buffer
     private int lineLength;
     private boolean breakLines; // Break lines at less than 80 characters

     /**
      * Constructs a {@link InputStream} in DECODE mode.
      *
      * @param in the <tt>java.io.InputStream</tt> from which to read data.
      * @since 1.3
      */
     public InputStream(java.io.InputStream in)
     {
        this(in, DECODE);
     } // end constructor

     /**
      * Constructs a {@link InputStream} in
      * either ENCODE or DECODE mode.
      * <p>
      * Valid options:<pre>
      *   ENCODE or DECODE: Encode or Decode as data is read.
      *   DONT_BREAK_LINES: don't break lines at 76 characters
      *     (only meaningful when encoding)
      *     <i>Note: Technically, this makes your encoding non-compliant.</i>
      * </pre>
      * <p>
      * Example: <code>new Base64.InputStream( in, Base64.DECODE )</code>
      *
      *
      * @param in the <tt>java.io.InputStream</tt> from which to read data.
      * @param options Specified options
      * @see Base64#ENCODE
      * @see Base64#DECODE
      * @see Base64#DONT_BREAK_LINES
      * @since 2.0
      */
     public InputStream(java.io.InputStream in, int options)
     {
        super(in);
        this.breakLines = (options & DONT_BREAK_LINES) != DONT_BREAK_LINES;
        this.encode = (options & ENCODE) == ENCODE;
        this.bufferLength = encode ? 4 : 3;
        this.buffer = new byte[bufferLength];
        this.position = -1;
        this.lineLength = 0;
     } // end constructor

     /**
      * Reads enough of the input stream to convert
      * to/from Base64 and returns the next byte.
      *
      * @return next byte
      * @since 1.3
      */
     public int read() throws IOException
     {
        // Do we need to get data?
        if (position < 0)
        {
           if (encode)
           {
              byte[] b3 = new byte[3];
              int numBinaryBytes = 0;
              for (int i = 0; i < 3; i++)
              {
                 try
                 {
                    int b = in.read();

                    // If end of stream, b is -1.
                    if (b >= 0)
                    {
                       b3[i] = (byte)b;
                       numBinaryBytes++;
                    } // end if: not end of stream

                 } // end try: read
                 catch (IOException e)
                 {
                    // Only a problem if we got no data at all.
                    if (i == 0)
                       throw e;

                 } // end catch
              } // end for: each needed input byte

              if (numBinaryBytes > 0)
              {
                 encode3to4(b3, 0, numBinaryBytes, buffer, 0);
                 position = 0;
                 numSigBytes = 4;
              } // end if: got data
              else
              {
                 return -1;
              } // end else
           } // end if: encoding

           // Else decoding
           else
           {
              byte[] b4 = new byte[4];
              int i = 0;
              for (i = 0; i < 4; i++)
              {
                 // Read four "meaningful" bytes:
                 int b = 0;
                 do
                 {
                    b = in.read();
                 }
                 while (b >= 0 && DECODABET[b & 0x7f] <= WHITE_SPACE_ENC);

                 if (b < 0)
                    break; // Reads a -1 if end of stream

                 b4[i] = (byte)b;
              } // end for: each needed input byte

              if (i == 4)
              {
                 numSigBytes = decode4to3(b4, 0, buffer, 0);
                 position = 0;
              } // end if: got four characters
              else if (i == 0)
              {
                 return -1;
              } // end else if: also padded correctly
              else
              {
                 // Must have broken out from above.
                 throw new IOException("Improperly padded Base64 input.");
              } // end

           } // end else: decode
        } // end else: get data

        // Got data?
        if (position >= 0)
        {
           // End of relevant data?
           if (/*!encode &&*/position >= numSigBytes)
              return -1;

           if (encode && breakLines && lineLength >= MAX_LINE_LENGTH)
           {
              lineLength = 0;
              return '\n';
           } // end if
           else
           {
              lineLength++; // This isn't important when decoding
              // but throwing an extra "if" seems
              // just as wasteful.

              int b = buffer[position++];

              if (position >= bufferLength)
                 position = -1;

              return b & 0xFF; // This is how you "cast" a byte that's
              // intended to be unsigned.
           } // end else
        } // end if: position >= 0

        // Else error
        else
        {
           // When JDK1.4 is more accepted, use an assertion here.
           throw new IOException("Error in Base64 code reading stream.");
        } // end else
     } // end read

     /**
      * Calls {@link #read()} repeatedly until the end of stream
      * is reached or <var>len</var> bytes are read.
      * Returns number of bytes read into array or -1 if
      * end of stream is encountered.
      *
      * @param dest array to hold values
      * @param off offset for array
      * @param len max number of bytes to read into array
      * @return bytes read into array or -1 if end of stream is encountered.
      * @since 1.3
      */
     public int read(byte[] dest, int off, int len) throws IOException
     {
        int i;
        int b;
        for (i = 0; i < len; i++)
        {
           b = read();

           //if( b < 0 && i == 0 )
           //    return -1;

           if (b >= 0)
              dest[off + i] = (byte)b;
           else if (i == 0)
              return -1;
           else break; // Out of 'for' loop
        } // end for: each byte read
        return i;
     } // end read

  } // end inner class InputStream

  /* ********  I N N E R   C L A S S   O U T P U T S T R E A M  ******** */

  /**
   * A {@link OutputStream} will write data to another
   * <tt>java.io.OutputStream</tt>, given in the constructor,
   * and encode/decode to/from Base64 notation on the fly.
   *
   * @see Base64
   * @since 1.3
   */
  public static class OutputStream extends java.io.FilterOutputStream
  {
     private boolean encode;
     private int position;
     private byte[] buffer;
     private int bufferLength;
     private int lineLength;
     private boolean breakLines;
     private byte[] b4; // Scratch used in a few places
     private boolean suspendEncoding;

     /**
      * Constructs a {@link OutputStream} in ENCODE mode.
      *
      * @param out the <tt>java.io.OutputStream</tt> to which data will be written.
      * @since 1.3
      */
     public OutputStream(java.io.OutputStream out)
     {
        this(out, ENCODE);
     } // end constructor

     /**
      * Constructs a {@link OutputStream} in
      * either ENCODE or DECODE mode.
      * <p>
      * Valid options:<pre>
      *   ENCODE or DECODE: Encode or Decode as data is read.
      *   DONT_BREAK_LINES: don't break lines at 76 characters
      *     (only meaningful when encoding)
      *     <i>Note: Technically, this makes your encoding non-compliant.</i>
      * </pre>
      * <p>
      * Example: <code>new Base64.OutputStream( out, Base64.ENCODE )</code>
      *
      * @param out the <tt>java.io.OutputStream</tt> to which data will be written.
      * @param options Specified options.
      * @see Base64#ENCODE
      * @see Base64#DECODE
      * @see Base64#DONT_BREAK_LINES
      * @since 1.3
      */
     public OutputStream(java.io.OutputStream out, int options)
     {
        super(out);
        this.breakLines = (options & DONT_BREAK_LINES) != DONT_BREAK_LINES;
        this.encode = (options & ENCODE) == ENCODE;
        this.bufferLength = encode ? 3 : 4;
        this.buffer = new byte[bufferLength];
        this.position = 0;
        this.lineLength = 0;
        this.suspendEncoding = false;
        this.b4 = new byte[4];
     } // end constructor

     /**
      * Writes the byte to the output stream after
      * converting to/from Base64 notation.
      * When encoding, bytes are buffered three
      * at a time before the output stream actually
      * gets a write() call.
      * When decoding, bytes are buffered four
      * at a time.
      *
      * @param theByte the byte to write
      * @since 1.3
      */
     public void write(int theByte) throws IOException
     {
        // Encoding suspended?
        if (suspendEncoding)
        {
           super.out.write(theByte);
           return;
        } // end if: supsended

        // Encode?
        if (encode)
        {
           buffer[position++] = (byte)theByte;
           if (position >= bufferLength) // Enough to encode.
           {
              out.write(encode3to4(b4, buffer, bufferLength));

              lineLength += 4;
              if (breakLines && lineLength >= MAX_LINE_LENGTH)
              {
                 out.write(NEW_LINE);
                 lineLength = 0;
              } // end if: end of line

              position = 0;
           } // end if: enough to output
        } // end if: encoding

        // Else, Decoding
        else
        {
           // Meaningful Base64 character?
           if (DECODABET[theByte & 0x7f] > WHITE_SPACE_ENC)
           {
              buffer[position++] = (byte)theByte;
              if (position >= bufferLength) // Enough to output.
              {
                 int len = Base64.decode4to3(buffer, 0, b4, 0);
                 out.write(b4, 0, len);
                 //out.write( Base64.decode4to3( buffer ) );
                 position = 0;
              } // end if: enough to output
           } // end if: meaningful base64 character
           else if (DECODABET[theByte & 0x7f] != WHITE_SPACE_ENC)
           {
              throw new IOException("Invalid character in Base64 data.");
           } // end else: not white space either
        } // end else: decoding
     } // end write

     /**
      * Calls {@link #write(int)} repeatedly until <var>len</var>
      * bytes are written.
      *
      * @param theBytes array from which to read bytes
      * @param off offset for array
      * @param len max number of bytes to read into array
      * @since 1.3
      */
     public void write(byte[] theBytes, int off, int len) throws IOException
     {
        // Encoding suspended?
        if (suspendEncoding)
        {
           super.out.write(theBytes, off, len);
           return;
        } // end if: supsended

        for (int i = 0; i < len; i++)
        {
           write(theBytes[off + i]);
        } // end for: each byte written

     } // end write

     /**
      * Method added by PHIL. [Thanks, PHIL. -Rob]
      * This pads the buffer without closing the stream.
      * @throws IOException
      */
     public void flushBase64() throws IOException
     {
        if (position > 0)
        {
           if (encode)
           {
              out.write(encode3to4(b4, buffer, position));
              position = 0;
           } // end if: encoding
           else
           {
              throw new IOException("Base64 input not properly padded.");
           } // end else: decoding
        } // end if: buffer partially full

     } // end flush

     /**
      * Flushes and closes (I think, in the superclass) the stream.
      *
      * @since 1.3
      */
     public void close() throws IOException
     {
        // 1. Ensure that pending characters are written
        flushBase64();

        // 2. Actually close the stream
        // Base class both flushes and closes.
        super.close();

        buffer = null;
        out = null;
     } // end close

     /**
      * Suspends encoding of the stream.
      * May be helpful if you need to embed a piece of
      * base640-encoded data in a stream.
      *
      * @since 1.5.1
      * @throws IOException
      */
     public void suspendEncoding() throws IOException
     {
        flushBase64();
        this.suspendEncoding = true;
     } // end suspendEncoding

     /**
      * Resumes encoding of the stream.
      * May be helpful if you need to embed a piece of
      * base640-encoded data in a stream.
      *
      * @since 1.5.1
      */
     public void resumeEncoding()
     {
        this.suspendEncoding = false;
     } // end resumeEncoding

  } // end inner class OutputStream

} // end class Base64
